I know different final drives can be better for different tracks, but I was wondering if anybody has any lap times showing the effects on times the lower final drive had(before and after). Thinking back on the couple of road courses I've driven, I can't imagine that the lower FD wouldn't benefit me in about every corner.

I realize that driver improvement could be a factor, but I was hoping to get a general feel the effects of lower final drives (ATS, JDM, anything) on lap times, whether they be good or bad.

Thanks

-and I've done several searches, but I'm looking for info on LAP TIMES

 

just curious

 

good question, i would like to know whos done this.

 

Problem is that changing a FD ratio isn't really something one can do between sessions, like shock or air pressure adjustments - so it's going to be near impossible to back-to-back a change like that.

Suffice to say that if I were given the choice between race-preparing the engine of my car or the gearbox (FD and diff), I'd do the 'box if I wanted to realize the biggest improvement in lap times.

K

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Knestis &raquo;</TD></TR><TR><TD CLASS="quote">

Suffice to say that if I were given the choice between race-preparing the engine of my car or the gearbox (FD and diff), I'd do the 'box if I wanted to realize the biggest improvement in lap times.

K</TD></TR></TABLE>



the benefits of a final drive make themselves manifest throughout the entire range of gears. Esp in a torqueless FF car like mine, a FD change can create a great improvement in exit speeds, and lessen the penalty for dropping out of the powerband vs a stock gearbox.

 

so has anyone actually went from one race season to the next with changing their final drive? and hitting the same track or tracks and noticed quicker times???? i know theres the possibility of losing top end and maybe maxing out that way!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Suffice to say that if I were given the choice between race-preparing the engine of my car or the gearbox (FD and diff), I'd do the 'box if I wanted to realize the biggest improvement in lap times.</TD></TR></TABLE>

I've heard the opposite said - that a gearbox will be worth a few tenths, and a motor can be worth a few seconds per lap.

Although building the motor can get more expensive.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itsdelsol &raquo;</TD></TR><TR><TD CLASS="quote">so has anyone actually went from one race season to the next with changing their final drive? and hitting the same track or tracks and noticed quicker times???? i know theres the possibility of losing top end and maybe maxing out that way!</TD></TR></TABLE>

i've never hit top speed on the track. in fact the thought of bouncing off the rev limiter in 5th actually scares the **** out of me

 

ive never heard of anyone bouncing off the rev limiter in 5th on a road course either, but i have heard thru a friend of mine that one of his customers actually hit 190km/h and couldnt go further on the HIGHWAY! he was using a different final drive, so i was wondering if anyone has hit it on a long straight-away. but the best way is to see back to back times from someone who has actually tried this!

 

We were seeing the shift lite in 5th coming off the banking (actually Walt got it once going into the banking with a great tow) at Lowes Motor Speedway w/ a 4.78 in my CRX. I am told that at Daytona we'd be rev-limited in 5th gear (which is why I assume the CFR guys do not run the 4.7x final drives).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itsdelsol &raquo;</TD></TR><TR><TD CLASS="quote">so has anyone actually went from one race season to the next with changing their final drive? and hitting the same track or tracks and noticed quicker times???? i know theres the possibility of losing top end and maybe maxing out that way!</TD></TR></TABLE>


130's at lowes with 4.785
126's at lowes with 4.9

most of that was ***** though...i grew some this year

cmp
154's 4.785
151's 4.9

vir north
148's 4.785
144's 4.9

summit
130
126

but this also could be experience and confidence gained on the track

 

Stunna-

HUGE GAIN!
Worth the investment? IYO is this a definite 'must have"?

 

In my opinion changing the final drive to just a JDM was the best mod I've ever done. Now I am switching to an ATS.

FYI-I am selling an extra new ATS FD.
https://honda-tech.com/zerothread?id=711755

 

now those are some numbers, thanks for the responses, im thinking of switching the b16's to that 4.9fd!

 

Notice that i was talking about replacing the FD and swapping an open diff for another option (pretty much any other option) as my first choice. I was also thinking in the realm of HC/IT-type cars where the engine gains will be more limited than would be the case if you put in a cam and raised the compression ratio...

K

 

I too saw about 2-3 seconds per lap with my 1st gen crx going from 4.428 to a 4.93 final drive.

the other part of this was the limited slip was installed at the same time. the courses were Grattan and Mid-Ohio, both courses I was quite familiar with. I would put them at about 2 seconds per lap. this was one of the biggest changes I ever saw in the car. the other was when i first took it from essentially showroom stock to ITA with the adjustable rear anti-roll bar.

I dare say you will NOT regret a better final drive. I found myself pulling good in third when I had been maxed out in 2nd or bogged in 3rd. there seemed to be several corners where this really helped me e.g., the keyhole at Mid-Ohio. getting a better jump off the turn onto the longest straight never hurts!

I suggest you think about the speeds, gears, you are normally in at the tracks you drive and then do the math. what gear and what rpm's were you normally in at the middle of the track and would it help if you changed the gearing about 10%.

You will also have to get used to a lot more shifting. at Grattan, I would normally be in 3rd gear for the whole course except for a single upshift/downshift on the main straight. Now I have a 5-3 downshift at the end of the main straight and then 3-4 before the "jump" back to 3 after the jump, up to 4 on the back straight (if you can call it that) and then 3-4 up the hill and 4-5 at the finish line down the main straight.

come to think about it, given the increased complexity of the driving, you will enjoy it more just from a driving experience even if you don't drop 2+ seconds!

 

I dropped 5 seconds at gingerman between R comps and a 4.40 to 4.785 change, but it was year to year.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ACRDC2 &raquo;</TD></TR><TR><TD CLASS="quote">Stunna-

HUGE GAIN!
Worth the investment? IYO is this a definite 'must have"?</TD></TR></TABLE>


ON A B16 a FINAL DRIVE 4.785 or 4.9 and LSD are what makes this engine come to life....on any other bseries it helps just as much....

anything under or at 4.4 needs to be 4.785 or higher!!!! even for a daily driver!!!

i m o of course

 

this is a great topic and great site, im buying myself the ATS final gear.

 

im sent!

 

ITA miata, 4.30 final drive at roebling 1:23.7

Same car, 4.88 final drive at roebling 1:25.7

There were things done to the car that SHOULD have made it faster when running the 4.88, but the gearing was all so wrong that it was slower.

The point made here is that shorter might be better on some tracks, but not all. you must research what tracks you are running....I cost myself an SIC win by not bringing the 4.30 with me that weekend.

 

A shorter FD will give you greater acceleration at speeds where you are in the same gear with it and without it, and poorer acceleration at speeds where it forces you into a higher gear.

If you spend a lot of a given track up close to redline, then the shorter FD will probably give you slower lap times because it is forcing you into a higher gear. If you spend a lot of another track well below redline, then the shorter FD will probably help.

In either case, though, the overall differences are going to be pretty small - and may very well be less than variations from one run to another, and one day to another. Also keep in mind that there are other factors that cause lap times to generally improve over time, such as greater familiarity with the track, greater confidence and willingness to push it, etc.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">In either case, though, the overall differences are going to be pretty small - and may very well be less than variations from one run to another, and one day to another. Also keep in mind that there are other factors that cause lap times to generally improve over time, such as greater familiarity with the track, greater confidence and willingness to push it, etc.</TD></TR></TABLE>

Out of curiosity, what is your experience with varying final drives to make this statement?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by phat-S &raquo;</TD></TR><TR><TD CLASS="quote">Out of curiosity, what is your experience with varying final drives to make this statement?</TD></TR></TABLE>

You mean, aside from the fact that I've driven otherwise similar cars with different final drives and gearing on various tracks, and seeing where they change the shift patterns and overall competitiveness/lap times? Or are you referring to my statement about the fact that lap times vary from run to run, and that they improve over time even without making any changes to the car's setup? Do you agree or disagree with that?

 

This is a topic I am very interested in as I ran the whole 2003 season on a stock tranny in the Si (well, 2 of them anyway). I've been saving for an LSD/FD and was also curious in laptime improvement. Though, nsxtasy's comment got me thinking about my home track and where I spend most of my time in the RPM band. I spend a good part in or at red-line, but there's also several places where the car just dogs itself trying to get up to speed where I think the FD will make a big difference. I'll also be adding an LSD though, so my lap time improvements will be a result from both, but interesting to see nonetheless.

-Ben, who plans on setting the ITA track record at Hallett in '04